Turning kitchen and yard waste into nutrients for plants

Thursday

Apr 25, 2013 at 9:38 AMApr 25, 2013 at 9:45 AM

MICKI BROWN, THE MOJAVE GARDENER

Gardening season is here and what better way than with compost to add organic material to the soil to grow veggies, flowers, shrubs and trees. You can buy compost at nurseries and garden centers, but why not make it yourself? For the most part, the ingredients can be found right in your own kitchen and yard.

Several years ago, I participated in a Master Composter training program held by the Mojave Desert & Mountain Recycling Authority/Master Composters. Upon completion, I became a certified Master Composter. Included in the experience was a promise to pass along what I learned to other residents of the High Desert.

Composting is nature's way of recycling plant materials into a product that can be used to enrich the soil and nourish plants. By adding compost, sandy soils retain water better, heavy soils are loosened and drainage is improved, and plant health is enhanced. Composting reduces the amount of waste discarded into the trash, thus sending less garbage to landfills.

Composting is partly art and partly science. Compost piles are actually microbial farms — bacteria are the most numerous decomposers and are the first to break down plant tissues. Later, fungi, protozoans, centipedes, millipedes, beetles, earthworms and others join in to do their part. Anything that grows is potential food for these decomposers. They use carbon from leaves and woody waste, and nitrogen from items like grass, weeds, manures, and fruit and vegetable waste from the kitchen.

Materials containing higher carbon content are considered "browns," while materials with higher nitrogen content are considered "greens." Recipes for the best compost can vary, but a good rule-of-thumb is a mix of 50-percent greens and 50-percent browns by volume.

Other materials that can be composted include egg shells, old flower bouquets, coffee grounds and filters, tea bags, paper towels and napkins.

Materials that should not be used in composting include oleander bushes, tamarisk/salt cedar, invasive weeds, meat, fish, dairy products, bones, fats, bread, large pieces of wood, pressure-treated wood, barbecue ashes, dog or cat wastes, and materials with spines or thorns (rose branches, cactus).

The more surface area the microorganisms have to work on, the faster the materials will decompose, so it's a good idea to run large pieces of waste such as branches through a chipping or shredding process before adding them to the compost pile. The microbes also need moisture and air. The best moisture level for the microbes and for faster composting should be that of a wrung out sponge. It is usually necessary to occasionally add water to the compost pile. It should also be turned periodically to get more air into the center. About once a week I add water to my compost bins. I turn it with a pitch fork whenever I add new materials, which is at least a couple times a week. Most of the contents I add are kitchen waste, chicken manure, wood shavings, straw, leaves and pine needles,

Large compost piles will insulate themselves and hold the heat given off by the microbes. The pile's center is warmer than its edges. The ideal compost pile is about 3x3x3 feet. Smaller piles have trouble retaining heat, while larger piles don't allow enough air into the center. Of course these proportions are only important for making compost quickly. Slower composting requires no exact proportions.

There are a number of ways to compost — some take less time and effort, some take more. The main things to consider are how much time you have to spend managing the pile, how much green waste your yard or kitchen generates, and how quickly you want the finished product. Two common methods include holding units and turning units. Each method has its own set of advantages and disadvantages.

Holding units are the "no fuss" method where you add as you go. You can build or purchase a bin approximately three-feet square, or just start a pile. Fill it up as materials become available — when it's full, start another pile — water and turn occasionally. I use two vented black bins, called Earth Machines, which have a removable lid on the top, and a door at the bottom for removing the finished product at the bottom of the pile. I also use two "Compost Orbs," which I purchased because they were supposed to be easy to roll them to where ever I needed them. They roll well when empty, or full of dry leaves, but not when they are full of heavy moist compost. I like my Earth Machines better. There are many composter models available, check them out and see what works best for you.

Turning units are the "active pile" method. These are usually a series of three or more units that allow garden wastes to be turned on a regular schedule. These are more appropriate for gardeners with a larger volume of waste, or for those who want to produce compost faster. Each bin should be about one cubic yard in size. Fill one bin by layering green materials with brown. Water the piles as you add layers. The pile will probably heat up — when it cools after a few days, turn the pile into an empty bin and water again, continue until the pile no longer heats up and materials are decomposed.

Now you know the basics of composting — an environmentally friendly method for dealing with all that yard and kitchen waste! For more information or to find out when their next free composting class will be offered, visit the Mojave Desert & Mountain Recycling Authority website at http://www.urecycle.org or call 1-888-URECYCLE (888-873-2925). You can also contact the Master Composter Coordinator, Don Woo, at composting@urecycle.org.

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